Integumentary System Flashcards Preview

A&P 400 > Integumentary System > Flashcards

Flashcards in Integumentary System Deck (105)
Loading flashcards...
0

The integumentary system includes:

1. Skin (cutaneous membrane)
-- epidermis
-- dermis
2. Accessory structures (hair, oil & sweat glands, sensory receptors).

1

Approximate how thick is the skin?

1-2 mm

2

Functions of integumentary system.

1. Regulates body temperature
2. Stores blood
3. Protection from external environment
4. Excretion and absorption
5. Sensation
6. Vitamin D synthesis

3

Epidermis vs Dermis

Epidermis
-- more superficial, thinner
-- contains epithelial tissue
-- somewhat avascular

Dermis
-- deeper and thicker
-- contains connective tissue
-- vascularized

4

Subcutaneous layer

AKA hypodermis

Not part of skin
Consists of areolar and adipose tissue

Functions: fat storage, blood vessel passage and location of pressure sensing nerve endings.

5

The epidermis is primarily composed of what tissue type?

Stratified squamous epithelium

6

4 principle cells of the epidermis

1 keratinocytes
2 melanocytes
3 Langerhans cell
4 Merkel cells

7

Keratinocytes

90% of epidermal cells

Produce keratin and lamellae granules

8

Keratin

Protein produced by keratinocytes

Protects skin and underlying tissue from heat, microbes and chemicals

Originate as tonofilaments which are converted by keratohyalin into keratin in the stratum granulosum.

9

Lamellae granules.

Released by keratinocytes in stratum granulosum and stratum corneum

Produce water repellant sealant
Decreases entry of water and foreign materials (and water loss too).

10

Melanocytes

In epidermis

Produce melanin

11

Melanin

Pigment produced by melanocytes and transferred to keratinocytes

Absorb damaging UV light
Shield nucleus of keratinocytes

12

Langerhans Cells

AKA Intraepidermal Macrophage cells

Epidermal dendritic cells
Arise from RBM and migrate to epidermis.

Participate in immune responses against invading microbes. Antigen presenting.

13

Merkel Cells

AKA tactile epithelial cells

Least numerous epidermal cell
In deepest layer of epidermis.

Contact Merkel/tactile disc. Detect touch.

14

Five layers of the epidermis

1. Stratum basale/germinativum
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum (palms and soles)
5. Stratum corneum

15

Stratum basale

AKA stratum germinativum

Deepest epidermal layer
SINGLE row of cuboidal or columnar keratinocytes

Also contain melanocytes, Merkel cells and stem cells (which produce keratinocytes)

If this layer is destroyed skin cannot regenerate

Cells attach to each other by desmosomes and to basement membrane by hemidesmosomes

16

Stratum spinosum

8-10 cells layers held together by desmosomes
Second deepest layer or epidermis

Mostly keratinocytes but also Langerhans cells and melanocyte projections.

17

Stratum granulosum.

Epidermis

3-5 layers of flat cells undergoing apoptosis

Transition layer between deeper active strata and superficial dead cells.

Keratinocytes release lamellae granules.
Contain keratohyalin which converts tonofilaments into keratin

18

Stratum lucidum

Layer of epidermis only found in finger tips, palms and soles of feet.

4-6 layers of flat dead cells.

Add additional toughness

19

Stratum corneum

25-30 layers of flat dead cells filled by keratin and surrounded by lipids

Most superficial layer of epidermis

Contain lamellar granules.

Protect against light, heat, chemicals and bacteria

20

Callus

Abnormal thickening of the stratum corneum of the epidermis due to friction.

21

Keratinization

Replacement of cell contents with keratin as cells move to skin surface

Takes 4-6 weeks.

Stem cells product keratinocytes.
Keratinocytes contain tonofilaments which are converted to keratin by keratohyalin in the stratum granulosum.

Epidermal growth factor (EGF) involved.

22

Dermis is composed primarily of what tissue type?

Dense irregular connective tissue containing collagen and elastin fibres

23

The Dermis contains:

Fibres (collagen and elastin)

Cells (fibroblasts, macrophages, fat cells)

Hair follicles, glands, nerves and blood vessels.

24

Elasticity

Ability to return back to the original shape

25

Extensibility

Ability to stretch

26

Tensile strength

Ability to resist pulling or stretching.

27

Two major regions of the dermis

Papillary and reticular

28

Papillary region

Top 20% of dermis

Thin collagen and elastic fibres
Mostly fibroblasts

Has dermal papillae (epidermal ridges)

29

Dermal papillae

AKA dermal ridges

Anchor papillary region of dermis to epidermis.
Increase surface area of papillary region
Contain capillaries that feed epidermis
Contain Meissner's corpuscles (touch) and free nerve endings that sense heat/cold/pain/tickling/itch